The present invention relates to hybrid-myeloma cells which produce monoclonal antibody specific to the .beta. subunit of human chorionic gonadotropin and to methods of use of the monoclonal antibody. The antibody of the present invention distinguishes the .beta. subunit of human chorionic gonadotropin even in the presence of intact human chorionic gonadotropin.
Myeloma cells from a mouse may be fused with lymphocytes from the spleen of a mouse immunized with a particular antigen to provide fused cells or hybrid-myeloma cells which are termed hybridoma cells. Hybridoma cells produce and secrete specific antibodies and are capable of rapid proliferation as well as indefinite maintenance. Furthermore, hybridoma cells can be manipulated by techniques applicable to animal cells in permanent culture. For example, individual cells can be cloned to provide progeny or clones which produce monoclonal antibodies each identically specific to a single antigenic determinant. Samples of the clones may be taken at any time and grown in culture or injected into animals for large scale production of a specific monoclonal antibody. Monoclonal antibodies produced in this way can be a versatile tool in a variety of areas including biological research and clinical medicine.
One problem researchers have encountered is that antisera produced from animals immunized with intact human glycoprotein hormones suffer from a lack of specificity for molecules within a species. The human glycoprotein pituitary hormones are composed of two dissimilar noncovalently bound .alpha. and .beta. subunits. The .alpha. subunit is common among pituitary glycoprotein hormones within a species. In contrast, the amino acid composition of the .beta. subunits are different and confer upon each glycoprotein hormone its unique biologic and immunologic activities. Antisera produced from animals immunized with intact glycoprotein hormones recognize determinant sites on both subunits and therefore suffers from a lack of specificity.
In accordance with the present invention, clone cells are provided which secrete antibody specific for the .beta.-subunit of human chorionic gonadotropin. The monoclonal antibody has little or no cross reactivity with intact human chorionic gonadotropin or with other glycoprotein pituitary hormones and their .beta. subunits in the range in which they would be expected to be present in serum. In addition, the present invention involves methods of use of the monoclonal antibody for tumor localization and/or treatment, affinity chromatography and determination of the structure of human chorionic gonadotropin.